In the packaging of substances, it is frequently desired to protect the substance from the outside environment with a package, while still allowing intermittent access to the substance. For example, where the substance is fructose-containing powdered beverage mix, it is desired to package a number of servings of such a powdered mix in a single package. Thus, a mechanism must be provided with the package for periodic access when the user wishes to remove a serving. However, in the interim (which may be days or even much longer), it is equally important that the powdered mix be completely protected or sealed from moisture in the surrounding environment.
While various packages of this type have been proposed in the prior art, various drawbacks have existed with such packages. Among the drawbacks has been: incomplete sealing of the substances from the environment, difficult access mechanisms, hard to handle packages, and hard to reseal packages.